IP Routing

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28 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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IP Routing

Kentaro Hayashi

Graduate school of Information Science and
Electrical Engineering

Department of Advanced Information Technology

Kyushu University

Contents


Routing



RIP



OSPF


Routing


The process of selecting paths in a network
along which to send network traffic.


Routing table


IP address : the destination


Metric : the cost of the path through


Next hop : the IP address of the next router

Routing table

172.16.250.0/24

172.16.252.0/24

172.16.251.0/24

.1

.2

.2

.1

.2

.1

172.16.50.0/24

172.16.1.0/24

192.168.1.0/24

172.16.100.0/24

.1

.1

.1

.1

IP address

metric

Next hop

192.168.1.0

0

-

172.16.1.0

0

-

172.16.251.0

0

-

172.16.250.0

0

-

172.16.100.0

1

172.16.251.2

172.16.50.0

1

172.16.250.2

172.16.252.0

1

172.16.251.2

1

172.16.250.2

Routing table


Static routing


Dynamic routing


Distance vector algorithms


RIP

IGRP


Link

state algorithms


OSPF


Dynamic Routing


IGP (Interior Gateway Protocol)


RIP (Routing Information Protocol)


OSPF (Open Shortest Path First)


EGP (Exterior Gateway Protocol)


BGP (Border Gateway Protocol)




AS (Autonomous System)

RIP (Routing Information Protocol)


The simple routing protocol


Used in small network


Distance vector algorithms


IGP


RFC 1058 (Charles Hedrick 1988)



RIP


RIP update


In RIP, all router can request to send update
information.


Broadcast


Every 30 seconds



RIP metric


The numbers of hop routers on path through


16 is infinity (15 is max)

Convergence


When the consistence of the network changed,
RIP update is sent. And the phase which all
routers in this RIP network received the RIP
update is called “Convergence”.



Update timer 30s


Invalid timer 180s


Flush timer 240s

Default route


Destination IP address is 0.0.0.0


Next hop is upper router

172.16.0.0/16

20 Subnet

192.168.0.0/16

20 Subnet

OSPF (Open Shortest Path First)


Used in large network


Link
-
state algorithms


IGP


Layer structure


RFC 2328 (1998)


Link
-
state algorithms


All router has network information. It is
called link state data base. And calculate
the shortest path to all host, using Shortest
Path First algorithm wrote by Dijkstra.

Area

Backbone area

Area 1

Area 3

Area 2